Budget ripole project with 2x 12" Visaton WHC30X

[meiborg]

Hello everyone,

I'm planning to build a ripole in a W-frame and I've come here for some advice on the cabinet. The goal is to build something nice on a budget there for I've selected cheap drivers from Visaton, the WHC30X 12". These drivers only cost 25 euro a piece, still there build quality is pretty decent and they sound pretty good. I've included a .pdf file with the parameters. The xmax of the driver isn't stated but I've read posts on a dutch forum where owners said the xmax is 9 millimeter.

I've been searching the Internet for all information I could find about ripole's and found that there's a lot of secrecy concerning the math and theorie on building a W-frame ripole. In some posts people stated that the reason is that Axel Ridthaler has a patent on it, perhaps that has something to do with it. I did find and use the the Q'n'D ripole calculation sheet here on diyaudio and used it to cook up a N-frame Ripole. I've included the the outcome of the filled in sheet for use with the WHC30x as an attachment as well.

So with the results of the sheet i can now build a N-frame ripole. My question is, can I simply combine the data for the N-frame ripole to build a W-frame ripole? In other words, do i simply place the drivers opposite of each other and take a 50% driver sd as front chamber sd instead of the 25% driver sd used for building a single ripole?

I've seen in some other ripole threads here on diyaudio that there are some members here who have a lot more knowledge on ripole theorie. I'd be much obliged if one (or some ) of you could shed some light on the matter, or atleast help me out with some suggestions for a W-frame ripole cabinet with the WCH30X drivers.

With kind regards,

Reinder

[5th element]

A bit of googling ironically turned up links to this thread.

Drivers / parameters for ripole subs

It might be of some use

[meiborg]

Hey,

Yes I've read the thread already, but thanks for your pointer! Think it was in that thread, someone posted two N-frames could be mirrored and the sd of the front chamber could be simply doubled as well. I have then kind of reverse engineered two W-frame ripole designs I found to check if that was correct. Both had drivers with an xmax of less then 10mm and still the sd of the front chamber, wich should then be about 50% sd of the driver if one could just double the sd of a N-frame, was in both cases more by a considerable amount.

That is why I'm hesitating if simply doubling the sd of the front chamber is indeed all there is to it.

With kind regards,

Reinder

[meiborg]

I got a step further again

Well, I'm still waiting for a bit of conformation on the mirroring of two N-Frame Ripole's but ofcourse in the meantime I'm trying to figure out if the N-frame dimensions from the Q'n'D sheet are accurate.

Since I read in the posts of Rudolf that one could simulate a Ripole in Hornresp as a frontloaded horn with vented rear chamber, i'd thought i'd give it a try! I am not 100% sure I got it all right in the first go but the frequency plot seems pretty much like what i was expecting.

I could do with some conformation whether I am on the right track here

With kind regards, Reinder

[meiborg]

Yes! My drivers arrived They look pretty dated, no vented polepiece or annything "fancy". The finnishing is decent though, it's all glued together nice and tidy, the stamped frame is decent. Not bad for such a modest price!

Still could use some help with the Hornresp simulation, I'm not sure if i did it correct.

Greetings Reinder

[BrianVG]

Hi meiborg,

I've got the same drivers, from Conrad, isn't it? I ordered them too a while ago.
Why did you choose a ripole? And not a normal closed enclosure?
I've come up with a 40l enclosure using Boxsim, but your calculations look much better!
I had planned to do woodworking next week, but this changed my mind! I already saw a thread on 'zelfbouwaudio' where someone made a ripole using these drivers, but I tought that a closed speaker cabinet would be better.

I'm looking forward to see your result!

[meiborg]

Hello Brian!

I chose for Ripole because it doesn't interact with the room the way "conventional" enclosures do. There's no boomyness or exagerated notes, it just sounds clean and effortless. Also, it reaches down deep without the need for a large enclosure. When desigmed properly, only marginal eq is needed for a flat freq. curve wich extends well into the 200 hz. They are the perfect company for the u frame speakers I will be building soon, very musical and not the boxy sound you get when building a, well, box

Ofcourse there is a trade-off. They don't pressurise the room like br, cb etc. do, you don't get the "ohh i feel it in my tummy" kinda experience. This makes them less suited for home cinema etc. The efficiency is also very low, multiple woofers and plenty of power are needed if you want to get a decent sound level.

I'll be using them for music only, for HT i got a conventional sub with pr's to shake the room .

greetings Reinder

[BrianVG]

Ok, I want to make a HT sub so I'll stick with my plan.

I hope to see a result of this project later on

[meiborg]

Hello,

Smal setback: Conrqad, the shop where iI ordered my drivers send me the wrong ones. They send the 4 ohmn versions instead of the 8 ohm ones. I've contacted them and "oh were terribly sorry sir but we don't have 8ohm versions at the moment".. Nice going guys. I'm a bit stuck on what to do now, send them back or use them in series. Originally i intended to drive them 4 ohms in paralel and power them with an UCD400 from Hypex.

Well, I'l give it some more thought

[BrianVG]

I'm not satisfied with the accuracy of Conrad. I often get wrong thing too.